<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width:100px;
            height:100px;
            background-color: red;
            margin:10px;
            color:#fff;
        }
        div:nth-child(2){
            background-color: blue;
            position: relative;
            left:0px;
            top:0px;
        }
        article{
            width:500px;
            height:300px;
            background-color: #ccc;
            position: relative;
        }
    </style>
</head>
<body>
    <!-- <div>div1</div>
    <div>div2</div>
    <div>div3</div> -->
    <article>
        <div>div1</div>
        <div>div2</div>
        <div>div3</div>
    </article>
</body>
</html>